Drive shaft positioning device associated with fuel injection pumps

ABSTRACT

For determining the fuel starting position of a drive shaft associated with a fuel injection pump, to the pump housing there is affixed a device which includes a locking pin shiftable into a position in which it drops into a notch on the drive shaft when the latter is in its previously determined fuel starting position.

United States Patent Staudt et al.

[54] DRIVE SHAFT POSITIONING DEVICE ASSOCIATED WITH FUEL INJECTION PUMPS[72] Inventors: Heinrich Staudt, Markgroningen- .Talhausen; RolfPrillwitz, Asperg,

both of Germany [73] Assignee: Robert Bosch GmbH, Stuttgart, Germany[22] Filed: Jan. 11, 1971 [21] Appl. No.: 105,537

[30] Foreign Application Priority Data Jan. 10, 1970 Germany ..P 20 00997.6

[52] US. Cl. ..92/15, 74/527, 123/139.13 [51] Int. Cl ..FlSb 15/76 [58]Field of Search.....74/55, 527; 123/139 13; 92/15 NOV. 14, 1972 [56]References Cited UNITED STATES PATENTS 3,552,219 l/1971 Berg ..74/552,407,696 9/ 1946 Webster ..74/527 3,183,739 5/1965 Rajewski ..74/552,624,327 1/1953 l-logeman ..l23/l39.l3 3,004,410 10/1961 Pierce..123/l39.l3 2,829,630 4/1958 Ziesche ..123/l39.13 2,743,594 5/1956 Hillet a1. ..l23/l39.13

Primary Examiner-Edgar W. Geoghegan Assistant Examiner-R. H. LazarusAttorney-Edwin E. Greigg [57] ABSTRACT For detemiining the fuel startingposition of a drive shaft associated with a fuel injection pump, to thepump housing there is affixed a device which includes a locking pinshiftable into a position in which it drops into a notch on the driveshaft when the latter is in its previously determined fuel startingposition.

4 Clains, 4 Drawing Figures PATENTEUnummn 3.702577 sum 1 or 2 mmvrons MW ,5

PATENTEDnuv 14 m2 3 I 702577 saw-2 0F 2 DRIVE SHAFT POSITIONING DEVICEASSOCIATED WITH FUEL INJECTION PUMPS BACKGROUND OF THE INVENTION Thisinvention relates to a fuel injection pump for internal combustionengines and concerns means for setting the pump drive shaft into apredetermined position, particularly into a position in which the pumpstarts its cycle of fuel delivery. This position of the pump drive shaftwill be referred to hereinafter as fuel starting position.

In fuel injection pumps of the aforenoted type it is a requirement todetermine the fuel starting position of, for example, the first cam onthe pump drive shaft (when viewed from the prime mover) to permit anattachment of the thus positioned fuel injection pump to thecorrespondingly present internal combustion engine.

For the purpose of identifying the fuel starting position, it is knownto provide two aligned line marks, one on a component rigidly affixed tothe pump drive shaft and one on the frontal face of the pump or toprovide a mark on the movable component if the stationary mark is on thepump housing.

The afore-outlined known setting procedure has, however, seriousdisadvantages. If the fuel injection pump is attached with a frontalflange to the gear box of the internal combustion engine, then thecoupling parts, such as the driving gear, are visible from the outsideonly with difficulty, if at all. In such a case it is very oftennecessary to find the fuel starting position anew in the pump attachedto the engine. This may be achieved by the so-called overrun method inwhich, for example, the pump suction chamber is placed under fuelpressure with the pressure valve removed, and the pump, with the driveshaft attached and stationary, is turned slowly to such an extent untilthe pump piston, during its upward stroke, closes the suction bore andthe outflow of test oil ceases. Upon such an occurrence the fuelinjection pump is tightened to the engine which was previously set to afuel starting position. Such a setting procedure is extremelytime-consuming and may be performed only by skilled labor. Even in caseof accessible line marks, the setting during installation on the engineis in a significant degree dependent upon the skill of the mechanic.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention toprovide an improved fuel injection pump which is so designed that it maybe attached rapidly to an internal combustion engine even by unskilledlabor and without the necessity of setting or testing steps and, duringthe course of repairs or maintenance work it may be set withoutadditional work to the same fuel starting position.

Briefly stated, according to the invention, with the fuel injection pumpthere is associated a device which is affixed to the fuel injection pumphousing in the vicinity of a component affixed to, and moving in unisonwith the pump drive shaft. The device includes a slidable locking pinwhich may be shifted into a notch which is provided in the periphery ofsaid component attached to the pump drive shaft and which is in registrywith the locking pin when the pump drive shaft is in the fuel startingposition. Thus, this positioning by means of cooperation between thelocking pin and the notch may be repeated at will without any effort andis in no way dependent upon the skill or attentiveness of the mechanic.This setting means is particularly advantageous in mass production, andresults in a time saving of up to percent of the mounting time neededheretofore.

Further, the setting by means of the aforeoutlined structure has greatsignificance in repair work because it may be performed by untrainedmechanics.

The invention will be better understood, as well as further objects andadvantages of the invention will become more apparent, from the ensuingdetailed specification of a preferred, although exemplary embodimenttaken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view of thepreferred embodiment of the invention in a disengaged position;

FIG. 2 is a sectional view of the same embodiment in a locking position;

FIG. 3 is an elevational view of the same embodiment as seen in thedirection of arrow III in FIG. 1; and

FIG. 4 is an elevational view of the same embodiment as it appears whenattached to the regulator housmg.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in FIGS. I-3, to amounting flange 12 of a pump housing 10 of a fuel injection pump 11,there is secured a locking device 13 by means of bolts 14 and nuts 15.

The device 13 comprises a support 16 that includes an integral mountingflange 17 and is provided with a centrally extending guide bore 19. Thelatter projects with substantial lateral play into an opening 28 of thepump housing 10. In addition, the openings 38 in the flange 17 are sodimensioned that bolts 14 passing through bores 38 permit such lateralplay. The purpose of the latter is the possibility of proper alignment(up or down, when viewed in FIG. 1) of the device 13 while being mountedon housing 10.

In the guide bore 19 there is disposed a locking pin 20, one terminus 21of which is preferably formed as a small sphere to avoid jamming. Theother terminus of locking pin 20 carries a disc-like collar 22 engagedby one end of a coil spring 23. The inner wall portions of housing 16define an annular space 24 into which the spring 23 extends. The end ofspring 23 remote from the collar 22 engages the base of annular space 24in support 16. The locking pin 20 is urged by spring 23 into its initialor inoperative position and abuts, as shown in FIG. 1, by means of acirclip 25 disposed adjacent the sphere 21, a frontal face 26 of thesupport 16. The circlip 25 further permits a simple installation of thelocking pin 20.

The annular space 24 is closed by means of a hollow threaded lid 31provided with a hexagonal head 30. The lid 31 clamps an O-ring 32against the support 16 thus providing a fluid-tight seal for the annularspace 24 with respect to the external environment.

In addition to the securing means 14, 15, the device 13 is immobilizedwith respect to the fuel injection pump 11 by means of a dowel pin 35which is force fitted in a bore 36 of the mounting flange 12 and in analigned bore 37 of the mounting flange l7.

The drive shaft 40 of the fuel injection pump 11 carries a fixedlyattached eccentric 41. The eccentric 41 has a notch 42 including twoaxially parallel lateral faces 43 which converge in the direction of thepump shaft axis. It is to be understood that the notch may also beprovided in a cylindrical collar keyed to the pump drive shaft 40, ormay be machined into the shaft 40 itself.

In FIGS. 1 and 2 there is further shown a cam 46 which is keyed to thepump drive shaft 40 and which causes reciprocation of a striker assembly45 which, in turn, causes a pump piston (not shown) to executealternating pressure and suction strokes. In FIG. 1 the cam 46 is shownin its upper dead center, while in FIG. 2 the cam 46 is in a fuelstarting position.

Turning now to FIG. 4, it is seen that the device 13, instead of beingattached to the pump housing 10, is affixed to the housing 49 of aregulator 48 that is fixedly secured to the fuel injection pump 11. Inthis structure, the notch which cooperates with the locking pin 20 isprovided in a component that is keyed to the drive shaft 40, such as adriving member of a centrifugal weighttype governor, or a gear if theregulator includes a stepup or step-down gear assembly.

OPERATION OF THE PREFERRED EMBODIMENT In the description that follows,the mounting and the operation of the device 13 will be set forth withreference to FIG. 2.

When the device 13 is mounted for the first time on the fuel injectionpump 11, the cam 46 of the drive shaft 40 is in the fuel startingposition and the notch 42 provided in the eccentric 41 is orientedtowards the device 13. The stroke portion traveled by the pump pistonor, the traveling path of the striker 45 up to the fuel startingposition is designated with H. The device 13, which at this point is notyet secured with the pin 35 (also, the bore 36 is not yet provided) andis thus only temporarily mounted, is loosened to such an extent that itmay be shifted as permitted by the clearance between opening 38 and theassociated bolt 14. The threaded lid 31 shown in FIG. 1 is removed.Thereafter, a force (such as thumb pressure) is exerted on the exposedcollar 22 resulting in an inward shift of locking pin 20 against theforce of the spring 23, until the spherical terminus 21 nests in thenotch 42. Thereby the support 16 has moved into its permanent, alignedposition; any tolerances in the machining of parts are thus compensated.Thereupon the nuts are tightened. The bore 36 is drilled in the mountingflange 12 through the preexistent bore 37 and then the dowel pin 35 isinserted. At this point the fuel starting position of the pump shaft 40is determined. The locking pin may be maintained in its engaged positionuntil the termination of the assembly by means of a separate threadedholding plate or the like inserted in the place of the threaded lid 31.

Subsequent to the setting and removal aforenoted holding plate, thelocking pin 20 is automatically withdrawn from the notch 42 by virtue ofthe force of spring 23, whereupon the threaded lid 31 is, subsequent toinserting the O-ring 32, positioned in place and tightened. It is thusseen that upon performing any subsequent repair or maintenance work, theproper setting of the fuel injection pump with respect to the drive camon the pump drive shaft ma be effected in a simple manner by means ofdevice 3. It suffices to remove lid 31, push the locking pin 20 inwardlyand rotate the shaft 40 until the head 21 of the locking pin 20 dropsinto the notch 42, thus immobilizing shaft 40.

What is claimed is:

1. In a fuel injection pump of the type including (a) a housing and (b)a pump drive shaft rotatably held in said housing, the improvementcomprising in combination A. means defining a notch on said pump driveshaft,

said notch rotating with said pump drive shaft as a unit and having twospaced lateral faces converging toward the pump drive shaft axis andextending parallel to the length dimension thereof and B. an indexingassembly secured to said housing and having 1. a support,

2. a locking pin axially slidably held in said support and adapted toassume an operative position in which it nests in said notch to indexsaid pump shaft in a predetermined angular position, said locking pinbeing adapted to assume a withdrawn position in which it allows anunobstructed rotation of said pump shaft,

3. a spring engaging said support and said locking pin to continuouslyurge the latter into its withdrawn position,

. means affixed to said locking pin and exposed to an arbitrarilyapplicable external force for moving said locking pin from saidwithdrawn position into said operative position against the force ofsaid spring,

5. first securing means adjustably attaching said support to saidhousing for setting the lateral position of said locking pin withrespect to said pump shaft,

6. second securing means for rigidly affixing said support to saidhousing subsequent to the setting of said lateral position.

2. An improvement as defined in claim 1, wherein said locking pin has aterminus of spherical configuration cooperating with said notch.

3. An improvement as defined in claim 2, wherein said terminus of saidlocking pin has a diameter smaller than the maximum distance and greaterthan the minimum distance between said two spaced converging lateralfaces of said notch.

4. an improvement as defined in claim 1, wherein said means defining anotch includes an eccentric affixed to said pump shaft.

1. In a fuel injection pump of the type including (a) a housing and (b)a pump drive shaft rotatably held in said housing, the improvementcomprising in combination A. means defining a notch on said pump driveshaft, said notch rotating with said pump drive shaft as a unit andhaving two spaced lateral faces converging toward the pump drive shaftaxis and extending parallel to the length dimension thereof and B. anindexing assembly secured to said housing and having
 1. a support,
 2. alocking pin axially slidably held in said support and adapted to assumean operative position in which it nests in said notch to index said pumpshaft in a predetermined angular position, said locking pin beingadapted to assume a withdrawn position in which it allows anunobstructed rotation of said pump shaft,
 3. a spring engaging saidsupport and said locking pin to continuously urge the latter into itswithDrawn position,
 4. means affixed to said locking pin and exposed toan arbitrarily applicable external force for moving said locking pinfrom said withdrawn position into said operative position against theforce of said spring,
 5. first securing means adjustably attaching saidsupport to said housing for setting the lateral position of said lockingpin with respect to said pump shaft,
 6. second securing means forrigidly affixing said support to said housing subsequent to the settingof said lateral position.
 2. An improvement as defined in claim 1,wherein said locking pin has a terminus of spherical configurationcooperating with said notch.
 2. a locking pin axially slidably held insaid support and adapted to assume an operative position in which itnests in said notch to index said pump shaft in a predetermined angularposition, said locking pin being adapted to assume a withdrawn positionin which it allows an unobstructed rotation of said pump shaft,
 3. aspring engaging said support and said locking pin to continuously urgethe latter into its withDrawn position,
 3. An improvement as defined inclaim 2, wherein said terminus of said locking pin has a diametersmaller than the maximum distance and greater than the minimum distancebetween said two spaced converging lateral faces of said notch.
 4. animprovement as defined in claim 1, wherein said means defining a notchincludes an eccentric affixed to said pump shaft.
 4. means affixed tosaid locking pin and exposed to an arbitrarily applicable external forcefor moving said locking pin from said withdrawn position into saidoperative position against the force of said spring,
 5. first securingmeans adjustably attaching said support to said housing for setting thelateral position of said locking pin with respect to said pump shaft, 6.second securing means for rigidly affixing said support to said housingsubsequent to the setting of said lateral position.